City Council Minutes 2017 12 19 - Laserfiche WebLink

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City Council Meeting Minutes December 19, 2017 Page 7 of 17 No public comments. Mayor Muckle closed the public hearing Councilmember Keany moved to approve Ordinance No. 1752, Series 2017, Councilmember Maloney seconded. Vote: Motion carried by unanimous roll call vote. DISCUSSION/DIRECTION/ACTION — COYOTE RUN SLOPE FAILURE INVESTIGATION AND MITIGATION OPTIONS Mayor Pro Tem Lipton stated he is recusing himself from this discussion as his property abuts Coyote Run and although not in the at risk area it is very near it He left the room Parks and Recreation Director Stevens stated in 2013 there appeared to be some soil movement at Coyote Run Open Space following the September 2013, 500 -year flood event. Based on continued observation, the City contacted American GeoServices, LLC to assess the site and complete a preliminary Geologic Hazard and Slope Stabilization evaluation which was completed in August 2015. As a result of continuous monitoring along with observations and concerns expressed by neighbors above the impacted area, City Council authorized a second study this past summer, the report for which is the Landslide Investigation & Mitigation Design report in the Council packet Director Stevens stated there are four options outlined in the report for moving forward. Some are short term and some are longer term. He introduced Sam Adettiwar, American GeoServices, LLC, which stated the slide has primanly occurred due to the excessive rainfall in 2013 and the local soil conditions on the slope. The majority of the Coyote Run corridor is under laid with these soils The borings revealed a slide of this magnitude and depth can occur anywhere in this open space corndor. Mr. Adettiwar outlined the four landslide repair options discussed in the report Option 1 Improve the drainage conditions to lower the water table to stabilize the ground It's not a complete fix but required at a minimum. Option 2. In addition to improving drainage conditions, build a retaining wall at the top. Option 3 In addition to improving drainage conditions and a retaining wall, remove and then, re -fill, compact and re -grade the slide mass to improve stability Options 4. Install horizontal and vertical drains and regrade the slide mass and build a buttress. Best and most cost effective option with the highest safety factor.